This invention relates to input/output processing, and more particularly input/output processing for performing retrieving, comparing calculation and collective calculation in a data base management system (hereinafter called as DBMS) in synchronism with a data transmitting operation.
For a user program to perform input/output requests, it must perform a concurrence control over the data before inputting the data from a recording medium. It must also assure that a buffer exists. If the data is distributed over a plurality of recording medium, the user program divides the requests for each recording medium and utilizes an accessing process, corresponding to a data format, to carry out the input/output operation. The accessing process outputs all requests for inputting a plurality of addresses of the data input requests. The data processing device processes the data in the order the requests are received. Then the user program carries out a data calculation for the received data.